HPL SAE 40 PCMO

You could very easily run the 15W-40 or straight 40 in Huntsville.
Thanks for the info!

We do get down to single digits in mornings during the winter here. This storm that’s coming in has us at -3f one of the days 🥶 and of course, that’s the day I have a surgery scheduled. 😒

Our winter 99% (Per NOAA) design temp is 20f, so maybe those super bitter mornings just stick out to me more.

Do you think there would even be a perceptible difference in lubricant performance (both seat of pants and oil analysis) between the 5w-40 and 15w-40?
 
I could use the SAE40 here in VA for most of the year, but like next week, temps will be in the teens and I think a 5W-40 will be better suited. No reason for me at least to use the 40 vs. 5W-40. Those Star VIIs work great to hold grade.
 
Huntsville has been absolutely wild ever since I got stationed here in 2010. The growth has been positively bonkers.
I lived in Alabama. It is not the city; it is everything else that comes with the state.
Simply, people are not that enthusiastic to leave. I am talking contractors, civilians.
 
Thanks for the info!

We do get down to single digits in mornings during the winter here. This storm that’s coming in has us at -3f one of the days 🥶 and of course, that’s the day I have a surgery scheduled. 😒

Our winter 99% (Per NOAA) design temp is 20f, so maybe those super bitter mornings just stick out to me more.

Do you think there would even be a perceptible difference in lubricant performance (both seat of pants and oil analysis) between the 5w-40 and 15w-40?
Yeah, our memory can over-represent the probability of isolated extreme cold snaps.

When I settled initially, I used an LLM tool to construct a table of percentile temperatures for the winter morning lows. I wanted to know what was the 90th percentile or the 95th percentile or 99th percentile for winter morning lows here.

That analysis convinced me that a 15w was *easily* viable in my area. ESPECIALLY when that 15w is a quality synthetic.

I’ve had a gallon each of 0w-40 Euro FS and 15w-40 Delo XSP in my trunk all winter. I’ve regularly opened the trunk in the morning and grabbed and shook each jug. Even at teens F, it was obvious that the Delo 15w would crank just fine. It was thick but still readily made “glug” and “gurgle” sounds when shaken.

It’s actually sort of surprising how little the difference between the 0w and 15 is at my “cold” temps of teens. I’m sure at around 0F the difference is quite pronounced and well below zero is where you will see the 15w and 0w separate into VERY different stories.

So the question for me came down to: how likely is it that I’m going to be stuck unable to crank my car because it’s too cold for the oil and I don’t have enough battery/starter? The answer was: so close to zero it’s essentially no real risk at all.

I don’t think that’s the case necessarily with the monograde SAE 40. But I still feel like I have a lot of cold margin with the 15w-40 and I want to see real world how the monograde fares in moderate Midwestern Winter. People here seem to think it gets cold, but since I grew up in WI and ND, I know that they have no idea what a REAL winter can do to cheap oils that don’t have good cold flow.

In my 18 years here in IN, we’ve had so few days in the low single digits or below that I think I could count them on one hand. We’re just not far enough North to get much of anything severe with any regularity.

The 15w-40 is IMO absolutely GTG here. We’ll see if the monograde is also.
 
Yeah, our memory can over-represent the probability of isolated extreme cold snaps.

When I settled initially, I used an LLM tool to construct a table of percentile temperatures for the winter morning lows. I wanted to know what was the 90th percentile or the 95th percentile or 99th percentile for winter morning lows here.

That analysis convinced me that a 15w was *easily* viable in my area. ESPECIALLY when that 15w is a quality synthetic.

I’ve had a gallon each of 0w-40 Euro FS and 15w-40 Delo XSP in my trunk all winter. I’ve regularly opened the trunk in the morning and grabbed and shook each jug. Even at teens F, it was obvious that the Delo 15w would crank just fine. It was thick but still readily made “glug” and “gurgle” sounds when shaken.

It’s actually sort of surprising how little the difference between the 0w and 15 is at my “cold” temps of teens. I’m sure at around 0F the difference is quite pronounced and well below zero is where you will see the 15w and 0w separate into VERY different stories.

So the question for me came down to: how likely is it that I’m going to be stuck unable to crank my car because it’s too cold for the oil and I don’t have enough battery/starter? The answer was: so close to zero it’s essentially no real risk at all.

I don’t think that’s the case necessarily with the monograde SAE 40. But I still feel like I have a lot of cold margin with the 15w-40 and I want to see real world how the monograde fares in moderate Midwestern Winter. People here seem to think it gets cold, but since I grew up in WI and ND, I know that they have no idea what a REAL winter can do to cheap oils that don’t have good cold flow.

In my 18 years here in IN, we’ve had so few days in the low single digits or below that I think I could count them on one hand. We’re just not far enough North to get much of anything severe with any regularity.

The 15w-40 is IMO absolutely GTG here. We’ll see if the monograde is also.
Thanks for the great reply. What is your 95% low temp you’ve calculated out in your area? It sounds like it’s not much different than mine and perhaps the 40 grade could be more well suited to my climate than I am willing to emotionally allow myself to believe.

NGL, you’ve got me looking at that 40 for my small engines. None of them run in temps cold enough to be of any concern, even the generator because it’s stored in the garage which is warmer than outdoor ambient because it’s under the house. Still wondering how well my Navigator would fare cranking that stuff in cold weather. It’s already a little sluggish with the PCMO 5w-40.
 
Thanks for the great reply. What is your 95% low temp you’ve calculated out in your area? It sounds like it’s not much different than mine and perhaps the 40 grade could be more well suited to my climate than I am willing to emotionally allow myself to believe.

NGL, you’ve got me looking at that 40 for my small engines. None of them run in temps cold enough to be of any concern, even the generator because it’s stored in the garage which is warmer than outdoor ambient because it’s under the house. Still wondering how well my Navigator would fare cranking that stuff in cold weather. It’s already a little sluggish with the PCMO 5w-40.
Definitely a YMMV situation, but the 5th percentile for my area is about 6F, so only a 5% chance of getting a temp colder than that.

On average there are 4 days a year below zero here, about 15-20 days per year below 10F, and 40-50 days per year below 20F.

We’re more than halfway through winter and I’ve never had a situation where the 15w-40 creates any concern at all that it wouldn’t crank. My Accord is still on its OEM battery (2022 model year) and it’s not a spring chicken nor particularly high grade compared to the X2 I’d normally buy.

When I determined the 15w was acceptable, I noted that the HPL’s CCS was about 6200 at -20C, which is -4F. There’s only about a 1% chance of that as a morning low in my area, and I’m garaging the car for most of the coldest days. So the worst start is after a cold soak in the work parking lot at closer to the afternoon high. It turns out my conversation with “Dr Rudnick” confirmed the cold start scuff wear doesn’t really accelerate until the oil exceeds 9000cP.

Excessively thick oil when cold is one of the easiest things to mitigate if one really wanted to. If you have a garage OR access to a block heater or oil pan heater, then it’s a non issue in many of the worst starts. If you live in ND and need to start your car at the end of the shift in -30F ambients, then you need a 0w oil and any consideration of less is not a great idea, IMO.

When it’s 10F outside, my garage is a balmy 45F. That’s effortlessly crankable all day long with SAE 40 monograde HPL.

“Dr Rudnick” indicates that startup scuff wear for cheap oil blends really spikes above 9000cP cranking viscosity. So if you are below the J300 rated points, you will have less than that. My 15w has about 6200cP at -20C. So in theory it’s fine down to -4F in terms of startup wear risk.

But in reality, it’s much better than fine because HPL blends 1) esters which have superb wetting for startup wear prevention, and 2) moly which has excellent anti-scuff when cold (unlike ZDDP which is useless at cold temps).

To wrap this up, HPLs blends make it very low risk to crank their oils all the way down to the SAE J300 test points for the winter rating. The 15w at -20C is not going to let your engine die.

The lower limit of the SAE 40 is the real open question in terms of a practical limit. Using 6000cP as a safety limit for viscosity, my analysis showed that the lower limit for cranking for the SAE 40 is about 15F. This is based on the Walther equation and some interpolating of points between 0F and 20F. At 15F, it’s about 5000cP.

Which is about what the 15w grade is at 0F. So the monograde loses about 15F of temperature at the lower cranking limit.

So if you NEVER see temps below 20F, IMO you can safely run the SAE 40 monograde all year long, giving a small buffer against the calculated 15F threshold.

It just so happens that the 5th percentile for afternoon temps (4-5pm) is just about 15F. So the monograde could work for me because 1) my morning start is almost always garaged, 2) my afternoon start is after a soak in warmer ambient temps that have only a 5% probability of approaching my cranking limit viscosity.

So the monograde is only a risk for me if the temp drops below the 5% chance value on a day I happen to go to the office, so a 3/7 chance times a 5% chance.

So there’s some significant reasons to think the SAE 40 could be acceptable even in my locality.


But the viability of the entire project turns on how the 15w-40 does at the 5k miles UOA. If it comes back as epic as the GX460 did, then it’s really, really hard to justify going for that last little bit with the monograde. It would be nice to trim out the VII and buff the AN, but the lab data might indicate there’s no real utility in it.

If so, I’ll blend in the SAE 40 in modest amounts and give it a good life.


Or just dump it all in the GX which I KNOW can handle the SAE 40 because of the short trip nature and always garaged first start (along with never sitting in one place for hours and hours that isn’t our warm garage).

The monograde I buy will get used, even if not as sole contents of my Accord.
 
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Do you think there would even be a perceptible difference in lubricant performance (both seat of pants and oil analysis) between the 5w-40 and 15w-40?
I think @Hohn has shown that this 15W-40 oil is an absolute beast of an oil. Did you see his UOA? Incredible. I think there is something to be gained from the reduced VIIs in the 15W-40.

I didn't realize Huntsville got that cold. However if he can run it in Indiana, I think you'd be ok in Huntsville. Are your cars garaged? On the chance you get down to single digits, I still think you'd be ok for a handful of starts a year. But if you're garaged, then you're definitely ok. I'm sure when you start again later in the day, it'll be warmer. I know how winter days are in the south. You need a coat in the morning, and sometimes short sleeves in the afternoon. He also posted a video of his cold start at 20F I believe, with the 15W-40. I think he's shown it's safe.

Edit: I see now that Hohn already gave you much more detailed and nuanced replies!
 
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Traction is a pretty unintuitive lubrication phenomenon. I like to think of it as how much “grip” is transmitted through two surfaces separated by the oil film when that film is highly constrained and highly loaded. It’s only of concern in full film lubrication when both surfaces are fully separated by an EHD oil film (right half beyond the “dip” in the Stribeck curve).

Generally, higher viscosity oils are higher traction oils, which makes sense because both are effectively a resistance to shear. But oils effectively change viscosity with the pressure acting on them. The rate at which this occurs is the pressure-viscosity coefficient.

For a given viscosity, a lower p-v coefficient will have lower traction (in general). This is how a PAO or GTL base oil can have lower pumping losses than a petroleum oil even if they have identical viscosity specs by KV100.

You want low traction because it means less pumping loss, a cooler running engine (less shear heating) and such.

But generally, thicker oils are higher traction oils and vice versa. So if you can have an oil that is lower traction *relative to HTHS or KV100* then you have the best of both worlds. Something that can protect like a thicker oils but with less of the penalty a thick oil would bring.

VII raise oil traction relative to KV100 because they have wildly different p-v coefficients than base oil. Using a no VII oil with a GTL base in a thicker grade gives you the minimum traction penalty relative to the HTHS and KV100. It sort of lets you have your thick oil cake and thin oil eat it too.

Anecdotally, my experience with the HPL PCMO 40 grades has shown no net decrease in MPG in similar duty cycles. The lower traction of the HPL oils is allowing me to have the thicker oil films (and lower wear) of the 40 grades while keeping the mpg of a 30 grade.
How are you determining lower wear is achieved?
 
I bit the bullet and decided to open the bottles and do a cold pour test after an overnight soak in my garage chest freezer.

As expected, the monograde is a bit thicker but still pours quite freely at about 0F temps. My freezer is more like -5F— -10f, but I’m sure the warmed slightly in the 30 seconds or so I had them sitting atop the freezer in ~45F.

This is not science, just a useful anecdotal comparison of the monograde against the 15w-40 that has been validated to temps of 15F in my personal usage.


For my purposes, this suffices to allay any lingering doubts about whether my local climate will allow the usage of this SAE 40 in my vehicles year round here in south central Indiana.

There are many levels to science, this is the ground floor and there’s nothing wrong with that. Thanks for the cool info. ;-)
 
screenshot-2026-01-25-at-2-54-03-pm-webp.321665


screenshot-2026-01-25-at-2-54-48-pm-webp.321666


Found these on Youtube. Thought they were interesting data points.
 
@Hohn - Any more cold temperature reports using the HPL SAE 40 in this -3 deg F weather in Indiana?

Supposed to be -8 deg F tonight in central Indiana's Putnam County.

Hope you are staying warm, sir!
 
@Hohn - Any more cold temperature reports using the HPL SAE 40 in this -3 deg F weather in Indiana?

Supposed to be -8 deg F tonight in central Indiana's Putnam County.

Hope you are staying warm, sir!

I'm not using any SAE 40 yet. But the 15w is working just fine in our GX which has been parked outside throughout all of this cold. You can tell the starter is working more than usual, as we're getting close to the 15w cranking temp limit (-20C).

Honestly, at -20C I'm expecting the monograde would be no-go. This is the temperature range where it certainly would require some "management" via block heater, pan heater, or simply being garaged and not allowed to get too cold. It's nearly a hard limit for 15w, never mind monograde.

At some point though, your battery's state of health is going to matter more for cranking performance than your oil grade. When I put the X2 battery in my van, I swear the cranking speed on the starter jumped by 20rpm. An unmistakable increase in cranking punch before and after in identical (warm) weather with identical oil.

Of course, that van has a 0w in it now, so it's sort of a cheat code with 0w and X2 battery.
 
I'm not using any SAE 40 yet. But the 15w is working just fine in our GX which has been parked outside throughout all of this cold. You can tell the starter is working more than usual, as we're getting close to the 15w cranking temp limit (-20C).

Honestly, at -20C I'm expecting the monograde would be no-go. This is the temperature range where it certainly would require some "management" via block heater, pan heater, or simply being garaged and not allowed to get too cold. It's nearly a hard limit for 15w, never mind monograde.

At some point though, your battery's state of health is going to matter more for cranking performance than your oil grade. When I put the X2 battery in my van, I swear the cranking speed on the starter jumped by 20rpm. An unmistakable increase in cranking punch before and after in identical (warm) weather with identical oil.

Of course, that van has a 0w in it now, so it's sort of a cheat code with 0w and X2 battery.
Thank you Hohn. Appreciate your information on the SAE40 HPL oil.

While my existing oil in the 5.7 Hemi 2022 RAM is HPL Premium Plus PCMO 0W-20, I have been talking with Dave at HPL about moving my motor's oil diet to HPL Supercar 0W-40 for my truck's year-round oil and something along the lines of 10K OCIs +/-.

The cold pour point of the HPL SAE40 is impressive to say the least but I remain a bit uncomfortable entertaining the mental idea of using it with the unpredictability of central Indiana's weather.

I have seen similar starter cranking effects in winter just with switching to a high cold cranking amp AGM-style battery. No cranking troubles at all (albeit 0W-20 still in the sump at present). I am a 3 years use and replace with a new battery follower.
 
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